1. Field of the Invention
The invention relates to the field of devices for measuring a dimension between crimped opposite sides of a terminal which has been crimped to an element.
2. Prior Art
A metal terminal is commonly attached to an end of an electrical conductor by crimping, i.e., deforming the terminal between opposed crimping dies until the deformed terminal tightly engages the end of the conductor disposed therein. The crimp height, i.e., the height or vertical dimension of the deformed terminal, very often is a good indicator of the quality of the crimp. The terminal must be deformed sufficiently to ensure a reliable electrical and mechanical connection with the conductor, but excessive deformation will overstretch the terminal and/or conductor, thereby weakening the connection or reducing electrical performance. Terminals and conductors are available in many different styles and sizes, and pullout tests and electrical performance tests are often performed on different combinations of the terminals and conductors to determine the crimp height which provides the best combination of resistance to separation of the terminal and conductor, and electrical performance. A target crimp height, plus or minus some tolerance, is then established as an acceptable crimp height for the particular combination of terminal and conductor.
The crimp height is measured with a micrometer or other measuring device having opposed cones or bars which are movable to engage the crimped terminal therebetween. However, some crimped terminals have unusual configurations, and the crimp height of such terminals is not accurately measurable by the common measuring instruments having opposed cones or bars. Other crimped terminals have a plastic insulation on the crimped portion of the terminal. The insulation deforms under point or edge loading applied by the opposing surfaces of the measuring instrument, thereby hindering accurate measurement of the crimp height.
Another problem encountered when measuring the crimp height of terminals with the plastic insulation sleeve is that the insulation often pulls up off of a concave surface of the terminal and forms a gap between the crimped terminal and the insulation. Again, accurate measurement of the crimp height is difficult or impossible.
Currently, crimp heights are not directly measured on terminals such as those discussed above. There is a need for an apparatus which enables non-destructive measurement of the crimp height of such terminals. The present invention provides an apparatus and method for non-destructive, direct measurement of the crimp height of terminals having unusual configurations or having insulation thereon.